Cooker Burner

ABSTRACT

The present invention discloses a cooker burner. The cooker burner comprises a base (1), a first ejector passage (3), a plurality of primary air passages (4), a cap (5) and a transfer passage (6), the base (1) has a chamber (11) and at least one first ejector (12); the first ejector passage (3) has a central chamber (311) and a peripheral chamber (312), the peripheral chamber (312) is used for making primary air around the periphery of the central chamber (311) uniform. With the design of the first ejector passage, the gas in the central chamber is more directly mix with the primary air in the peripheral chamber, improving the mixing uniformity and air intake rate around the periphery of the central chamber. Therefore, yellow flame and backfire can be avoided.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a burner for gas cookers, and in particular to a top-air-intake cooker burner having two passages.

BACKGROUND OF THE INVENTION

At present, among commercially available gas cookers such as panel gas cookers and embedded gas cookers, a burner of the embedded gas cooker is of a top-air-intake structure with a single passage through which the gas enters, and the flame size is controlled by a valve, so the gas cannot be used for an inner flame ring separately.

To solve the problems of no separate central flame and low thermal load arising from the single passage, a Chinese patent CN1212348A discloses a gas burner which is simple in structure and can separately adjust central and outer ring flames, i.e., the burner is generally provided with a central ejector and an outer ring ejector. However, such gas burner is experimentally found to have unsatisfactory combustion performance, with uneven velocities of the primary air supply to a central flame port and external flame ports. Moreover, incomplete mixing of gas and primary air may also result in different flame lengths between the central and outer ring flames due to uneven air intake for the center and outer ring ejectors. At the same time, the ejector tube cannot be too long as it is limited by the height of the top-air-intake burner, resulting in a large passage resistance, and yellow flames tend to appear when the power is high, especially at a low heat position.

To solve the above problems, a Chinese patent CN2427756Y provides a solution. Specifically, an auxiliary passage is additionally provided beside the original single main passage, so that the auxiliary passage is directly communicated with an internal combustion ring, the gas can enter a gas mixing chamber through the two passages at the same time, and the main passage can be closed and the auxiliary passage can be used separately during combustion. Cookers of this structure can be used with both inner and outer flame rings open, or with the outer flame ring closed and the inner flame ring open separately, as required, and the flame size is controlled by a switch, which can cook dishes and also save fuel gas and reduce pollution. However, since only one auxiliary passage corresponding to an inner ring gas ejector is additionally provided beside the main passage corresponding to an outer ring gas ejector and eccentrically disposed relative to the main passage, the pressure of gas flowing out of flame ports circumferentially arranged in a small cap corresponding to the auxiliary passage is uneven, resulting in uneven flames produced by the inner ring of the small cap.

To avoid the problem of uneven flames, for another example, a Chinese patent CN204026673U refers to a top-air-intake burner, comprising a main body base fixed on a bottom case, wherein the bottom case is totally closed with no holes in the bottom, and three ejectors, namely two outer ring ejectors and one inner ring ejector, are provided on the main body base fixed to a panel. After a main body and the main body base are mounted, the center lines of the ejectors correspond to those of an outer ring Venturi tube and an inner ring Venturi tube. The high velocity fluid ejected from the ejectors tends to produce a negative pressure, allowing air, which does not flow into the main body but is directly obtained from the atmosphere and transferred to the vicinity of the ejectors, to be drawn in at the Venture tubes. Moreover, the two outer ring ejectors are located on both sides of the inner ring ejector, and the entire ring of the outer ring cap corresponding to the two outer ring ejectors is interconnected. Once one of the two outer ring ejectors is blocked, the gas ejected therefrom will partially flow through the outer ring cap back into the gas passage corresponding to the blocked outer ring ejector, which may cause an explosion if too much gas collects.

SUMMARY OF THE INVENTION

It is a first object of the present invention to provide a cooker burner which can effectively improve the mixing uniformity of primary air and gas.

It is a second object of the present invention to provide a cooker burner which is less prone to yellow flames and small fire.

For achieving the above objections, the cooker burner comprises:

a base having a chamber with an upward opening and a first ejector disposed at the center of the chamber;

a connector disposed on the base, which comprises a plate body and a first ejector passage vertically disposed at the center of the plate body, the plate body having an flange extending in the horizontal direction to cover the chamber;

a plurality of primary air passages disposed at intervals along the periphery of the connector, enabling introduction of air from the outside into the chamber of the base;

a cap disposed on the connector, a first gas mixing chamber at the center and a second gas mixing chamber surrounding the first gas mixing chamber respectively defined between the cap and the connector; the first gas mixing chamber corresponding to the first ejector passage to mix the primary air and gas from the first ejector;

a transfer passage for transferring the mixed primary air and gas from the first gas mixing chamber to the second gas mixing chamber;

wherein

the first ejector passage has a central chamber located at the center of the first ejector passage and a peripheral chamber surrounding the central chamber and separated from the central chamber; a bottom inlet of the central chamber is in communication with the chamber of the base and faces to the first ejector, and a top outlet of the central chamber is communicated with the first gas mixing chamber; and a bottom opening of the peripheral chamber is in communication with the chamber of the base, and the top of the peripheral chamber is a closed end.

The first ejector passage is defined by a tubular body having a top opening and a bottom opening, the tubular body comprises an annular inner wall and an annular outer wall disposed apart from the inner wall, and the central chamber is defined inside the inner wall, and the peripheral chamber is defined between the inner wall and the outer wall, and top of the inner wall is connected to the top of the outer wall forming the closed end, by which the gas in the central chamber can be directly mixed with the primary air in the peripheral chamber in more excellent manner, thus avoiding the collision between the gas and the primary air converged from different directions, further improving the distribution uniformity of the primary air around the central chamber, improving the primary air intake rate and effectively reducing the kinetic energy loss at the same time.

Preferably, the bottom of the outer wall of the peripheral chamber is lower than that of a wall of the central chamber. Under this design, the primary air and the gas can be premixed downstream of the central chamber and then drawn into the first gas mixing chamber for secondary mixing with the aid of the low pressure caused by Venturi effect obtained in the first gas mixing chamber, thus effectively improving the mixing uniformity of primary air and gas.

To further improve the mixing uniformity of primary air and gas, the cap has an upwardly facing groove for receiving the first ejector passage, the groove and the plate body forming the first gas mixing chamber, and a lower surface of a top wall of the groove and a closed end of the first ejector passage forming a radial Venturi cavity. At the same time, the radial Venturi cavity may also effectively reduce the height of the burner. Of course, a gas mixing chamber with the Venturi effect cavity, such as an axial Venturi cavity, may also be adopted.

The radial Venturi cavity may be formed in the following way. The closed end of the first ejector passage has a first end face disposed horizontally and a second end face slopes downwardly from a lower edge of the first end face; when the relation among a vertical distance D1 between the first end face and the lower surface of the top wall of the groove, a vertical distance D2 between an upper edge of the second end face and the lower surface of the top wall of the groove, and a vertical distance D3 between a lower edge of the second end face and the lower surface of the top wall of the groove meets D1<D2<D3, the radial Venturi cavity is formed.

Preferably, an included angle α between the first end face and the second end face is 5°-15°. If the angle α is too large, the burner will be too high with an increase in its volume, it will make it difficult to meet the requirements of the embedded gas cookers. If the angle α is too small, the airflow resistance will be large and the effect on reducing the airflow resistance and the volume of the cavity will not be obvious.

Preferably, the cap has an inner ring portion and an outer ring portion concentrically disposed at intervals, and the groove is disposed inside the inner ring portion with a top end thereof higher than that of the outer ring portion; the inner ring portion has an annular wall protruding upward and a main cap plate covering over the annular wall, and a plurality of main flame grooves and a plurality of flame holding grooves are disposed at intervals along the circumferential direction on the annular wall, and a plurality of main fire ports and flame holding ports respectively in coordination with the outer wall of the main cap plate.

The second gas mixing chamber may be formed in the following way. The outer ring portion has an inner ring wall surface and an outer ring wall surface concentrically disposed apart, and a bottom wall connecting the inner ring wall surface and the outer ring wall surface; an auxiliary cap plate covers over the inner ring wall surface and the outer ring wall surface, and the inner ring wall surface, the outer ring wall surface, the bottom wall and the auxiliary cap plate forming the second gas mixing chamber.

Preferably, a plurality of first main flame branches and a plurality of second main flame branches are disposed at intervals along an upper surface of the outer ring wall surface, and the first main flame branch has a depth greater than that of the second main flame branch. The first main flame branch has a depth greater than that of the second main flame branch, so a gap can be formed therein to supply secondary air.

Preferably, a plurality of secondary air holes are disposed at intervals at the periphery of the plurality of main flame grooves and the plurality of flame holding grooves, the secondary air holes are located on the junction of the inner ring wall surface and the annular wall, and each secondary air hole is in communication with the secondary air passage below the cap.

The primary air passage may be provided using any of tubes in the prior art communicating the outside with the chamber of the base, and may also be provided using any of tubes in the prior art communicating the outside to the secondary air holes. In the present invention, to achieve a simple and compact structure of the burner, the primary air passage and the secondary air passage are formed in the following way. Preferably, Each secondary air hole has a plurality of annular peripheral walls protruding downward, the annular peripheral walls are enclosed to form annular chambers, and a plurality of radial secondary air passages for communicating the annular chambers with the outside are disposed along the circumferential direction of the connector; the primary air passages are radially disposed along the circumferential direction of the connector, and the secondary air passages and the primary air passages are spaced apart.

The secondary air passages and the primary air passages are spaced in the following way. At least one pair of baffles are disposed circumferentially and radially along the plate body extending the lower surface of the plate body of the connector downward; when each pair of baffles is placed on the base, a gap is formed between of the baffles and the base forms an air inlet of the primary air passage.

Preferably, a notch is disposed on the inner ring wall surface of the outer ring portion, the annular peripheral walls of the adjacent annular chambers are enclosed forming a cavity, and the notch is communicated with the cavity, the notch and the cavity together form the transfer passage.

In order for the user to control the central flame produced by the inner ring portion and the peripheral flame produced by the outer ring portion of the burner independently, preferably, a third gas mixing chamber is fluidly separated from the first gas mixing chamber and the second gas mixing chamber, and is formed between the annular wall of the inner ring portion and the main cap plate; the chamber of the base has at least one second ejector, and at least one second ejector passage is disposed on the base and is independent of the first ejector passage, the second ejector passage is fluidly connected to the base and the second ejector. The fuel mixture of the third gas mixing chamber is directly supplied through the second ejector passage, and is fluidly separated from the first gas mixing chamber and the second gas mixing chamber, so that it can be supplied independently.

Preferably, at least one through hole is disposed on an inner circumference of the annular wall of the inner ring portion on the top wall of the cap, the through hole has a convex wall protruding downward, a chamber formed by enclosing the convex walls has a top opening through which the fuel mixture in the second ejector passage enters the third gas mixing chamber. Of course, in the present invention, the second ejector passage and the third gas mixing chamber may be jointly confined in an axial Venturi tube and other convergent-divergent tubular structures extending along the axial direction of the base, and the tubular structure is formed partially in the cap and partially in the base.

According to the above inventive concept, preferably, the second ejector passage is an axial Venturi tube.

To avoid as much as possible the risk of gas backflow due to blockage of the ejectors, which could lead to an explosion, preferably, at least one partition plate is disposed on the top wall of the cap, the partition plate partitions the third gas mixing chamber into two independent chambers, and each independent chamber is in communication with a corresponding second ejector passage. The independent chamber can effectively prevent the gas from flowing back due to the blockage of one of the second injectors, thus causing an explosion.

To control the gas flame size of the burner by a valve, the inner and outer flame rings may be used simultaneously or the inner flame ring may be used separately. Especially, the internal, central and external flames are virtually free of turbulence and interference in the circumferential direction, and a function of cooking with small flames is also achieved. Preferably, a partition plate is disposed between the annular wall protruding upward of the inner ring portion and the main cap plate, and at least one gas outlet for the outflow of the fuel mixture mixed in the third gas mixing chamber is disposed on a top surface of the partition plate; a first gap is disposed between a lower surface of the partition plate and an upper surface of the inner ring portion, and a second gap is disposed between an upper surface of the partition plate and the main cap plate, and the second gap serves as a flame outlet of the inner ring portion.

In order to make the partition plate and the main cap plate match with each other, preferably, a convex ring protrudes upward at the center of the upper surface of the inner ring portion, and a mounting hole is disposed at a corresponding position of the partition plate and is capable of placing on the convex ring; an outer edge of the partition plate abuts against the annular wall, at least two ribs for supporting the main cap plate are disposed at intervals on the upper surface of the partition plate along the circumferential direction, and the main cap plate extends downward at a position corresponding to the convex ring forming an annular convex wall, the annular convex wall is capable of running through the mounting hole and is adapted to the convex ring.

Compared with the prior art, the present invention has the following beneficial effects: with the sandwich structure design of the first ejector passage, the peripheral chamber located in the outer layer enables the primary air entering the chamber to be more evenly distributed around the periphery of the central chamber, so that, under the action of the first ejector, the gas in the central chamber can be more directly mixed with the primary air homogenized in the peripheral chamber, thus avoiding the collision between the gas and the primary air converged from different directions, further improving the mixing uniformity of primary air and gas, improving the primary air intake rate and effectively reducing the kinetic energy loss at the same time. Therefore, the flames of the top-air-intake burner are short, uniform and powerful, and defects such as yellow flame and backfire are avoided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a cooker burner according to an embodiment of the present invention;

FIG. 2 is an exploded perspective view of FIG. 1;

FIG. 3 is a vertical sectional view of FIG. 1 from one view;

FIG. 4 is an enlarged view of Part-Ain FIG. 3;

FIG. 5 is a perspective view of a first ejector passage and a second ejector passage according to the embodiment of the present invention;

FIG. 6 is a vertical sectional view of FIG. 1 from another view;

FIG. 7 is a perspective view of a cap from front view according to the embodiment of the present invention;

FIG. 8 is a perspective view of the cap from back view according to the embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be further described below in detail by an embodiment with reference to the accompanying drawings.

FIGS. 1-8 show a preferred embodiment of a top-air-intake cooker burner according to the present invention. The cooker burner may be applied to the traditional top-air-intake burners and also to the Italian Sabaf burners in Europe. The cooker burner comprises a base 1, a connector 2 disposed on the base 1, a plurality of primary air passages 4, a cap 5 disposed on the connector 2, and a transfer passage 6.

The base 1 has a chamber 11 with an upward opening and a first ejector 12 disposed at the center of the chamber 11;

the connector 2 disposed on the base 1, which comprises a plate body 21 and a first ejector passage 3 vertically disposed at the center of the plate body 21, the plate body 21 having an flange 211 extending in the horizontal direction to cover the chamber 11;

the primary air passages 4 are disposed at intervals along the periphery of the connector 2, enabling introduction of air from the outside into the chamber 11 of the base 1;

the cap 5 disposed on the connector 2, a first gas mixing chamber 514 at the center and a second gas mixing chamber 525 surrounding the first gas mixing chamber 514 respectively defined between the cap 5 and the connector 2; the first gas mixing chamber 514 corresponding to the first ejector passage 3 to mix the primary air and gas from the first ejector.

The transfer passage 6 for transferring the mixed primary air and gas from the first gas mixing chamber 514 to the second gas mixing chamber 525.

In order to effectively improve the mixing uniformity of primary air and gas, the first ejector passage 3 has a central chamber 311 located at the center of the first ejector passage 3 and a peripheral chamber 312 surrounding the central chamber 311 and separated from the central chamber 311; a bottom inlet of the central chamber 311 is in communication with the chamber 11 of the base 1 and faces to the first ejector 12, and a top outlet of the central chamber 311 is communicated with the first gas mixing chamber 514; and a bottom opening of the peripheral chamber 312 is in communication with the chamber 11 of the base 1, and the top of the peripheral chamber 312 is a closed end 33.

In this embodiment, the first ejector passage 3 is defined by a tubular body having a top opening and a bottom opening, the tubular body comprises an annular inner wall 31 and an annular outer wall 32 disposed apart from the inner wall 31, and the central chamber 311 is defined inside the inner wall 31, and the peripheral chamber 312 is defined between the inner wall 31 and the outer wall 32, and top of the inner wall 31 is connected to the top of the outer wall 32 forming the closed end 33, by which the gas in the central chamber 311 can be directly mixed with the primary air in the peripheral chamber 312 in more excellent manner, thus avoiding the collision between the gas and the primary air converged from different directions, further improving the distribution uniformity of the primary air around the central chamber 311, improving the primary air intake rate and effectively reducing the kinetic energy loss at the same time. At the same time, the bottom of the outer wall 32 of the peripheral chamber 312 is lower than that of a wall of the central chamber 311. With this design, the primary air and gas can be premixed downstream of the central chamber and then drawn into the first gas mixing chamber 514 for secondary mixing with the aid of the low pressure caused by Venturi effect obtained in the first gas mixing chamber 514, thus effectively improving the mixing uniformity of primary air and gas.

Specifically, the first gas mixing chamber 514 is preferably disposed inside the cap 5 and the cap 5 has an upwardly facing groove 511 for receiving the first ejector passage 3, the groove 511 and the plate body 21 of the connector 2 forming the first gas mixing chamber 514, and a lower surface of a top wall of the groove 511 and a closed end 33 of the first ejector passage 3 forming a radial Venturi cavity 60. The radial Venturi cavity 60 is formed in the following way, the closed end 33 of the first ejector passage 3 has a first end face 331 disposed horizontally and a second end face 332 slopes downwardly from a lower edge of the first end face 331; when the relation among a vertical distance D1 between the first end face 331 and the lower surface of the top wall of the groove 511, a vertical distance D2 between an upper edge of the second end face 332 and the lower surface of the top wall of the groove 511, and a vertical distance D3 between a lower edge of the second end face 332 and the lower surface of the top wall of the groove 511 meets D1<D2<D3, the radial Venturi cavity 6 is formed. More preferably, an included angle α between the first end face 331 and the second end face 332 is 5°-15°, preferably 10° in this embodiment.

Since the radial Venturi cavity 6 of the first ejector passage 3 and the first gas mixing chamber 514 are directly disposed from 90° vertically to horizontally, other interconnecting pieces are omitted to reduce local resistance loss. At the same time, the included angle α can reduce the resistance loss when the mixture of gas and primary air is ejected into the second gas mixing chamber 525, and make the ejection and transition smoother. On the premise of ensuring that the local resistance loss can be effectively reduced, the included angle α is also less likely to result in an excessively large ejector pipe.

In addition, the second gas mixing chamber 525 can be formed in the following way. The cap 5 has an inner ring portion 51 and an outer ring portion 52 concentrically disposed at intervals, and the groove 511 is disposed inside the inner ring portion 51 with a top end thereof higher than that of the outer ring portion 52; the inner ring portion 51 has an annular wall 512 protruding upward and a main cap plate 513 covering over the annular wall 512, and a plurality of main flame grooves 5121 and a plurality of flame holding grooves 5122 are disposed at intervals along the circumferential direction on the annular wall 512, and a plurality of main fire ports and flame holding ports respectively in coordination with the outer wall 32 of the main cap plate 513. The outer ring portion 52 has an inner ring wall surface 521 and an outer ring wall surface 522 concentrically disposed apart, and a bottom wall 523 connecting the inner ring wall surface 521 and the outer ring wall surface 522; an auxiliary cap plate 524 covers over the inner ring wall surface 521 and the outer ring wall surface 522, and the inner ring wall surface 521, the outer ring wall surface 522, the bottom wall 523 and the auxiliary cap plate 524 forming the second gas mixing chamber 525. At the same time, a plurality of first main flame branches 5221 and a plurality of second main flame branches 5222 are disposed at intervals along an upper surface of the outer ring wall surface 522, and the first main flame branch 5221 has a depth greater than that of the second main flame branch 5222, so a gap can be formed therein to supply secondary air.

In order to supply the secondary air to the central flame produced by the inner ring portion 51, a plurality of secondary air holes 7 are disposed at intervals at the periphery of the plurality of main flame grooves 5121 and the plurality of flame holding grooves 5122, the secondary air holes 7 are located on the junction of the inner ring wall surface 521 and the annular wall 512, and each secondary air hole 7 is in communication with the secondary air passage below the cap 5 and further comprises a portion which can subtly serve as the transfer passage 6. Specifically, each secondary air hole 7 has a plurality of annular peripheral walls 71 protruding downward, the annular peripheral walls 71 are enclosed to form annular chambers, and a plurality of radial secondary air passages 40 for communicating the annular chambers with the outside are disposed along the circumferential direction of the base 1. At the same time, a notch 5211 is disposed on the inner ring wall surface 521 of the outer ring portion 52, the annular peripheral walls 71 of the adjacent annular chambers are enclosed forming a cavity, and the notch 5211 is communicated with the cavity, the notch 5211 and the cavity together form the transfer passage 6. Similarly, the primary air passages 4 are radially disposed along the circumferential direction of the base 1. The secondary air passages 40 and the primary air passages 4 are partitioned by at least one pair of baffles 212 are disposed circumferentially and radially along the plate body 21 extending the lower surface of the plate body 21 of the connector 2 downward; when each pair of baffles 212 is placed on the base 1, a gap is formed between of the baffles 212 and the base 1 forms an air inlet of the primary air passage 4. The significance of partition is to effectively partition the primary air passages and the secondary air passages 40 to avoid mutual influence.

In order for the user to control the central flame produced by the inner ring portion 51 and the peripheral flame produced by the outer ring portion 52 of the burner independently, a third gas mixing chamber 8 is fluidly separated from the first gas mixing chamber 514 and the second gas mixing chamber 525, and is formed between the annular wall 512 of the inner ring portion 51 and the main cap plate 513; the chamber 11 of the base 1 has at least one second ejector 9, and at least one second ejector passage 10 is disposed on the base 1 and is independent of the first ejector passage 3, the second ejector passage 10 is fluidly connected to the base 1 and the second ejector 9. The fuel mixture of the third gas mixing chamber 8 is directly supplied through the second ejector passage 10 and fluidly separated from the first gas mixing chamber 514 and the second gas mixing chamber 525, so that it can be supplied independently. In this embodiment, there are two second ejector passages 10 symmetrically disposed on both sides of the first ejector passage 3 along the circumferential direction, so as to uniformly produce the central and peripheral flames at the same time. In addition, two corresponding through hole 50 is disposed on an inner circumference of the annular wall 512 of the inner ring portion 51 on the top wall of the cap 5, the through hole 50 has a convex wall 501 protruding downward, a chamber formed by enclosing the convex walls 501 has a top opening through which the fuel mixture in the second ejector passage 10 enters the third gas mixing chamber 8.

According to the present invention, in order to enhance the ejection capacity, the second ejector passage 10 and the third gas mixing chamber 8 may be jointly confined in an axial Venturi tube and other convergent-divergent tubular structures extending along the axial direction of the base 1, and an opening of the axial Venturi tube is formed partially in the cap 5, corresponding to the chamber formed by enclosing the convex walls 501 of the through hole 50, and partially in the connector 2, corresponding to the second ejector passage 10. In order to avoid gas backflow due to blockage of any of the second ejectors, which may cause the cooker burner to explode, corresponding to the arrangement of the two through holes 50, a partition plate 20 is disposed on the top wall of the cap 5, the partition plate 20 partitions the third gas mixing chamber 8 into two independent chambers, such as a first independent chamber 201 and a second independent chamber 201′, and each independent chamber is in communication with a corresponding second ejector passage (10). In addition, a partition plate 30 is disposed between the annular wall 512 protruding upward of the inner ring portion 51 and the main cap plate 513, and a plurality of gas outlets 301 for the outflow of the fuel mixture mixed in the third gas mixing chamber 8 is disposed on a top surface of the partition plate 30; a first gap 302 is disposed between a lower surface of the partition plate 30 and an upper surface of the inner ring portion 51, and a second gap 303 is disposed between an upper surface of the partition plate 30 and the main cap plate 513, and the second gap 303 serves as a flame outlet of the inner ring portion 51. As the partition plate 30 has the effect of further reducing the gas velocity, the central flame of the inner ring and the small flame produced by the flame outlet are more uniform, so that the bottom of a pan is heated more uniformly. When in use, such a structure, in conjunction with a segmented gas valve, may make the inner ring portion 51 and the outer ring portion 52 of the cap 5 produce flames at the same time, and may also make the inner ring portion 51 produce flames separately and the two rings of the inner ring portion 51 produce flames at the same time, so that different flame sizes are available to suit different food preparation and different stages of cooking, making it easy to use. In order to facilitate mounting the partition plate 30, a convex ring 510 protrudes upward at the center of the upper surface of the inner ring portion 51, and a mounting hole 304 is disposed at a corresponding position of the partition plate 30 and is capable of placing on the convex ring 510; an outer edge of the partition plate 30 abuts against the annular wall 512, at least two ribs 305 for supporting the main cap plate 513 are disposed at intervals on the upper surface of the partition plate 30 along the circumferential direction, and the main cap plate 513 extends downward at a position corresponding to the convex ring 510 forming an annular convex wall 5130, the annular convex wall 5130 is capable of running through the mounting hole 304 and is adapted to the convex ring 510.

Referring to FIG. 6, as described above, the paths (see dotted arrows) of the primary air, gas and mixed primary air and gas inside the burner are as follows. Due to the low pressure caused by the ejection of gas from the first ejector 12 to the first ejector passage 3 and gas in the first gas mixing chamber 514 with a radial Venturi effect, the primary air is drawn from the outside into the peripheral chamber 312 of the chamber 11 of the base 1 through the primary air passage 4 (for brevity, only one first ejector passage 3 and one transfer passage 6 are shown), and then transferred into the central chamber 311 by the kinetic energy of the gas itself for premixing the primary air and gas. Finally, the primary air and gas are further mixed in the radial Venturi effect cavity of the first gas mixing chamber 514 and enter the second gas mixing chamber 525 through the transfer passage 6. The mixed primary air and gas finally flow out through the first main flame branch 5121 and the second main flame branch 5122 of the outer ring portion 52 and are ignited together with the secondary air in the external environment to form peripheral flames. The cap 5 further comprises a central flame which can be separately controlled by the user, and the primary air and gas required for the central flame are fed into the third gas mixing chamber 8 through the second ejector passage 10 independently of the first ejector passage 3. At the same time, the third gas mixing chamber 8 is separated from the first gas mixing chamber 514 and the second gas mixing chamber 525, thus achieving a fluid separation between the second gas mixing chamber 525 and the third gas mixing chamber 8, which can then be supplied separately to allow the user to control the inflow of the fuel mixture into the first ejector passage 3 and the second ejector passage 10 independently, and to adjust the size of the peripheral and central flames simply by adjusting a control valve connected to a gas inlet end of an input passage. 

1. A cooker burner, comprising: a base (1) having a chamber (11) with an upward opening and a first ejector (12) disposed at the center of the chamber (11); a connector (2) disposed on the base (1), which comprises a plate body (21) and a first ejector passage (3) vertically disposed at the center of the plate body (21), the plate body (21) having an flange (211) extending in the horizontal direction to cover the chamber (11); a plurality of primary air passages (4) disposed at intervals along the periphery of the connector (2), enabling introduction of air from the outside into the chamber (11) of the base (1); a cap (5) disposed on the connector (2), a first gas mixing chamber (514) at the center and a second gas mixing chamber (525) surrounding the first gas mixing chamber (514) respectively defined between the cap (5) and the connector (2); the first gas mixing chamber (514) corresponding to the first ejector passage (3) to mix the primary air and gas from the first ejector; and a transfer passage (6) for transferring the mixed primary air and gas from the first gas mixing chamber (514) to the second gas mixing chamber (525); wherein, the first ejector passage (3) has a central chamber (311) located at the center of the first ejector passage (3) and a peripheral chamber (312) surrounding the central chamber (311) and separated from the central chamber (311); a bottom inlet of the central chamber (311) is in communication with the chamber (11) of the base (1) and faces to the first ejector (12), and a top outlet of the central chamber (311) is communicated with the first gas mixing chamber (514); and a bottom opening of the peripheral chamber (312) is in communication with the chamber (11) of the base (1), and the top of the peripheral chamber (312) is a closed end (33).
 2. The cooker burner of claim 1, wherein the first ejector passage (3) is defined by a tubular body having a top opening and a bottom opening, the tubular body comprises an annular inner wall (31) and an annular outer wall (32) disposed apart from the inner wall (31), and the central chamber (311) is defined inside the inner wall (31), and the peripheral chamber (312) is defined between the inner wall (31) and the outer wall (32), and top of the inner wall (31) is connected to the top of the outer wall (32) forming the closed end (33).
 3. The cooker burner of claim 1, wherein the bottom of the outer wall (32) of the peripheral chamber (312) is lower than that of a wall of the central chamber (311).
 4. The cooker burner of claim 2, wherein the cap (5) has an upwardly facing groove (511) for receiving the first ejector passage (3), the groove (511) and the plate body (21) forming the first gas mixing chamber (514), and a lower surface of a top wall of the groove (511) and a closed end (33) of the first ejector passage (3) forming a radial Venturi cavity (60).
 5. The cooker burner of claim 4, wherein the closed end (33) of the first ejector passage (3) has a first end face (331) disposed horizontally and a second end face (332) slopes downwardly from a lower edge of the first end face (331); when the relation among a vertical distance D1 between the first end face (331) and the lower surface of the top wall of the groove (511), a vertical distance D2 between an upper edge of the second end face (332) and the lower surface of the top wall of the groove (511), and a vertical distance D3 between a lower edge of the second end face (332) and the lower surface of the top wall of the groove (511) meets D1<D2<D3, the radial Venturi cavity (60) is formed.
 6. The cooker burner of claim 5, wherein an included angle α between the first end face (331) and the second end face (332) is 5°-15°.
 7. The cooker burner of claim 4, wherein the cap (5) has an inner ring portion (51) and an outer ring portion (52) concentrically disposed at intervals, and the groove (511) is disposed inside the inner ring portion (51) with a top end thereof higher than that of the outer ring portion (52); the inner ring portion (51) has an annular wall (512) protruding upward and a main cap plate (513) covering over the annular wall (512), and a plurality of main flame grooves (5121) and a plurality of flame holding grooves (5122) are disposed at intervals along the circumferential direction on the annular wall (512), and a plurality of main fire ports and flame holding ports respectively in coordination with the outer wall (32) of the main cap plate (513).
 8. The cooker burner of claim 7, wherein the outer ring portion (52) has an inner ring wall surface (521) and an outer ring wall surface (522) concentrically disposed apart, and a bottom wall (523) connecting the inner ring wall surface (521) and the outer ring wall surface (522); an auxiliary cap plate (524) covers over the inner ring wall surface (521) and the outer ring wall surface (522), and the inner ring wall surface (521), the outer ring wall surface (522), the bottom wall (523) and the auxiliary cap plate (524) forming the second gas mixing chamber (525).
 9. The cooker burner of claim 8, wherein a plurality of first main flame branches (5221) and a plurality of second main flame branches (5222) are disposed at intervals along an upper surface of the outer ring wall surface (522), and the first main flame branch (5221) has a depth greater than that of the second main flame branch (5222).
 10. The cooker burner of claim 8, wherein a plurality of secondary air holes (7) are disposed at intervals at the periphery of the plurality of main flame grooves (5121) and the plurality of flame holding grooves (5122), the secondary air holes (7) are located on the junction of the inner ring wall surface (521) and the annular wall (512), and each secondary air hole (7) is in communication with the secondary air passage below the cap (5).
 11. The cooker burner of claim 10, wherein each secondary air hole (7) has a plurality of annular peripheral walls (71) protruding downward, the annular peripheral walls (71) are enclosed to form annular chambers, and a plurality of radial secondary air passages (40) for communicating the annular chambers with the outside are disposed along the circumferential direction of the connector (2); the primary air passages (4) are radially disposed along the circumferential direction of the connector (2), and the secondary air passages (40) and the primary air passages (4) are spaced apart.
 12. The cooker burner of claim 11, wherein at least one pair of baffles (212) are disposed circumferentially and radially along the plate body (21) extending the lower surface of the plate body (21) of the connector (2) downward; when each pair of baffles (212) is placed on the base (1), a gap is formed between of the baffles (212) and the base (1) forms an air inlet of the primary air passage (4).
 13. The cooker burner of claim 12, wherein a notch (5211) is disposed on the inner ring wall surface (521) of the outer ring portion (52), the annular peripheral walls (71) of the adjacent annular chambers are enclosed forming a cavity, and the notch (5211) is communicated with the cavity, the notch (5211) and the cavity together form the transfer passage (6).
 14. The cooker burner of claim 7, wherein a third gas mixing chamber (8) is fluidly separated from the first gas mixing chamber (514) and the second gas mixing chamber (525), and is formed between the annular wall (512) of the inner ring portion (51) and the main cap plate (513); the chamber (11) of the base (1) has at least one second ejector (9), and at least one second ejector passage (10) is disposed on the base (1) and is independent of the first ejector passage (3), the second ejector passage (10) is fluidly connected to the base (1) and the second ejector (9).
 15. The cooker burner of claim 14, wherein at least one through hole (50) is disposed on an inner circumference of the annular wall (512) of the inner ring portion (51) on the top wall of the cap (5), the through hole (50) has a convex wall (501) protruding downward, a chamber formed by enclosing the convex walls (501) has a top opening through which the fuel mixture in the second ejector passage (10) enters the third gas mixing chamber (8).
 16. The cooker burner of claim 15, wherein the second ejector passage (10) is an axial Venturi tube.
 17. The cooker burner of claim 15, wherein at least one partition plate (20) is disposed on the top wall of the cap (5), the partition plate (20) partitions the third gas mixing chamber (8) into two independent chambers (201, 201′), and each independent chamber is in communication with a corresponding second ejector passage (10).
 18. The cooker burner of claim 14, wherein a partition plate (30) is disposed between the annular wall (512) protruding upward of the inner ring portion (51) and the main cap plate (513), and at least one gas outlet (301) for the outflow of the fuel mixture mixed in the third gas mixing chamber (8) is disposed on a top surface of the partition plate (30); a first gap (302) is disposed between a lower surface of the partition plate (30) and an upper surface of the inner ring portion (51), and a second gap (303) is disposed between an upper surface of the partition plate (30) and the main cap plate (513), and the second gap (303) serves as a flame outlet of the inner ring portion (51).
 19. The cooker burner of claim 18, wherein a convex ring (510) protrudes upward at the center of the upper surface of the inner ring portion (51), and a mounting hole (304) is disposed at a corresponding position of the partition plate (30) and is capable of placing on the convex ring (510); an outer edge of the partition plate (30) abuts against the annular wall (512), at least two ribs (305) for supporting the main cap plate (513) are disposed at intervals on the upper surface of the partition plate (30) along the circumferential direction, and the main cap plate (513) extends downward at a position corresponding to the convex ring (510) forming an annular convex wall (5130), the annular convex wall (5130) is capable of running through the mounting hole (304) and is adapted to the convex ring (510). 